Compression control valve



April 23, 1968 R. J. MORSE COMPRESSOR CONTROL VALVE Filed Nov. 5, 1965 5RE m 0% n m m W 2 O 8 N f 46 -F 6 4 6 I A 3 m 1 a 4 6 E 4 5 3 w 4 fI R 8v 5 7- l J m7 M x i O 5 V 2 2 Y I 06 m 2 B R W. 5 4 h 6 T m 8 V 7 2 m aS I E R, I O 4 T FROM PRESSURE sou United States Patent Ofi ice 3,379,21 1 Patented Apr. 23, 1968 3,379,211 COMPRESSION CONTROL VALVERobert J. Morse, Elyria, Ohio, assignor to Bendix-WestlnghouseAutomotive Air Brake Company, Elyria, Ohio, a corporation of DelawareFiled Nov. 5, 1965, Ser. No. 506,485 9 Claims. (Cl. 137-469) Thisinvention relates to fluid pressure responsive valves and moreparticularly to a valve for automatically controlling the delivery ordischarge side of an air compressor.

The broad object of the present invention is to provide an improvedvalve responsive to the delivery pressure of an air compressor andadapted to be interposed between the delivery side of a compressor and afluid pressure receiver or reservoir to serve the combined func tions ofa governor, discharge line unloader, check valve, drain valve and safetyvalve.

In the copending application of Valentine et al., Ser. No. 267,986,filed Mar. 26, 1963, now Patent No. 3,329154 and assigned to the sameassignee as the present invention, there is disclosed a compressordischarge line control Valve which includes a piston between an inletand delivery cavity with the piston carrying a oneway check valve whichpermits the passage of fluid from the inlet cavity to the deliverycavity but not in the reverse direction. At the end of the inlet cavityopposite the piston there is an exhaust port controlled by a fluidpressure responsive valve member which is normally urged to closedposition by a spring surrounding a piston and the valve. Because thepressure acting on the upper and lower sides of the piston issubstantially equal, when the pressure in the inlet cavity acting on thevalve produces a force in excess of the spring force, the valve is firstcracked, and then is moved by the pressure in the inlet cavity to itsfully open position. The compressor is now unloaded and the piston andvalve remain in unloading position until the reservoir pressure recedesto a predetermined low value whereupon the spring moves the piston andthe valve toward their closed position and as soon as the valve is movedinto its fully closed position the compressor again beings the deliveryof fluid through the check valve in the piston to the reservoir.

For maximum efiiciency, it is highly desirable that the exhaust valve,after initial cracking, move to its fully opened position with asnap-action and this can be achieved by providing the valve with anadded area upon which the pressure in the inlet cavity can act followinginitial valve cracking. An added area, while achieving snap-actionopening, can some times impede the closing of the valve in that as thevalve approaches its nearly closed position and while still cracked, thepressure in the inlet cavity equalizes with that across the seat andaround the restricted area between the body and valve so that valve doesnot close positively. One of the objects of the present invention is toeliminate the foregoing undesirable characteristic by the provision ofadded-area means which are available and effective when the valve isbeing moved to open position but which automatically retracts so as notto impede movement of the valve to its closed position.

More particularly it is an object of the invention to provide in anunloading valve of the type described, means for insuring positive andeflicient movement of the unloading valve element to its open and closedpositions.

Other objects and their attendant advantages will become apparent as thefollowing description is read in conjunction with the accompanyingdrawings wherein:

FIG. 1 is a vertical cross-sectional view of a compressor control valveincorporating the features of the present invention;

FIG. 2 is an enlarged broken, vertical cross-sectional view showing adetail of the present invention;

FIG. 3 is a view similar to FIG. 2 but showing the parts of theinvention in changed positions; and

FIG. 4 is a broken, vertical, cross-sectional view showing a modifiedform of the invention.

Referring now to the drawings, FIG. 1 discloses a valve including ahollow body member 10 having an interiorly threaded open top closed by acap member 12 having an outlet or delivery port 14 therethrough whichserves to connect a delivery cavity 15 in the body 10 with a fluidpressure reservoir (not shown). The body 10 has an inlet port 16 in theside thereof which is adapted to be connected to the delivery side of anair compressor with the port 16 leading to an inlet cavity 18 within thebody 10 whose lower side includes a flange 20 surrounding an exhaustport 22 controlled by an exhaust or unloader valve 24 defined by araised annular ring on the upper side of a circular disc 25 and whichnormally sealingly engages the underside of the flange 20 to close theexhaust port 22. The delivery cavity 15 in the body 10 is separated fromthe inlet cavity 18 by a piston 28 having fluid passages 30 extendingtherethrough whose upper ends are controlled by a check valve 32 whichis normally urged on to an annular valve seat 34 by means of a spring 36operating between the upper side of the valve 32 and a flange 38 at alower end of the delivery port 14.

Connected to the piston 28 is a piston rod 40 which extends axiallydownwardly and outwardly of the exhaust port 22 and surrounding thepiston rod is a compression spring 41 which operates between the innersurface of the flange 20 and the lower side of the piston 28. The lowerend of the rod 40 is threaded to receive a nut 42 whose upper end bearsagainst the lower side of an aligning member 44 engaging the lowersurface of a shallow cup shaped member 46 having an upstanding annularwall 48 and received within the cup shaped member 48 is theaforementioned disc member 25 having on its upper side the annular valvemember 24 which is urged to its normal closed position by the action ofthe spring 41 on the piston.

In accordance with the invention the member 25 is centrally counterboredto provide an enlarged central passage 52 surrounding a portion of thepiston rod 40. The member 25 has also formed therein an annular groove54 of substantial depth which is connected to the central passage 52 bya series of radial passages 56. When pressure exists in the inlet cavity18 and hence in the groove 54 it is prevented from leaking downwardlybetween the inner edge of the cup shaped member 46 and the rod 40 bymeans of an O-ring 62 around the inner upper edge of the aligning member44 as can be clearly seen in FIG. 1.

As can be seen particularly in FIGS. 2 and 3, the vertical wall 48 ofthe cup-shaped member 46 is selected so as to have .a height such thatthe upper edge of the wall 48 extends above the lower face of the groove54 and received within the groove 54 is an O-ring 58 which slidingly andsealingly engages the upper and lower faces of the groove. Also receivedin the groove 54 outwardly of the O-ring 58 is a split expanding metalring 60 which is expanded outwardly when sufiicient pressure operates onthe O-ring 58 to expand this member radially until the ring engages thevertical wall 48 of the cup-shaped member 46 which limits the expansionof the ring 60 as shown in FIG. 2. When the pressure operating on theO-ring 58 is release-d to atmosphere the split ring 60 and the O-ring 58retract to a free state wherein the split ring moves substantially awayfrom the vertical wall 48 and into the groove 54 thereby providing alarge clearance area between the disc 25 and the wall 66, as shown inFIG. 3.

In operation with the delivery port 14- connected to a fluid pressurereservoir and the inlet port 16 connected to a compressor, when thelatter is operating it delivers fluid pressure by way of inlet port 16to the inlet cavity 18 from which the fluid flows by way of passages 3%in the piston 28, by the check valve 32 and through the delivery port 14to the reservoir. As the pressure builds up in the reservoir it likewisebuilds up in the inlet cavity 18 and because the pressure forces actingon the upper and lower sides of the piston 28 are subsantially equal,there is a resultant pressure force which operates across the areadefined by the exhaust valve 24 and this same pressure also feedsthrough the central passage 52 and the radial passages 56 to the groovespace 54 inwardly of the O-riug 58 to expand this radially outwardlyuntil the split ring engages the vertical wall 48 of the cup shapedmember 46.

As the expanding or split ring 66 expands outwardly it approaches theinner annular wall 66 in an inverted annular exhaust cavity 68 in thelower end of the body 16. It will be noted that the upper wall of thecavity 68 is also the seat for the exhaust valve 24 so that when thevalve 24 is moved to open position fluid in the inlet cavity 18 flowspast the valve 24 and then outwardly to atmosphere initially along thewall 66. Thus, when the split ring 60 is moved close to the wall 66 asshown in FIG. 2, a restriction 70 is provided between the wall 66 andthe split ring 60 whereby the free escape of fluid to atmosphere isprevented so that it operates with substantially full force across thearea or the disc outwardly on the valve 24 plus the added area definedby the upper surface of the ring 60. Thus with pressure suddenly exertedon this entire area immediately following cracking of the valve 24, thevalve 24 and hence the piston 28 are moved downwardly against the upwardforce of the spring 41 with a positive snap action with the pressure inthe inlet cavity 18 immediately receding to atmospheric and the pressurein the reservoir now acting downwardly on the piston 28 and the checkvalve 32 to retain the exhaust valve 24 in its fully open position sothat the compressor is unloaded with any water trapped between thecompressor and the inlet cavity being discharged to atmosphere as thevalve 24 is moved to open position. As soon as the pressure in the inletcavity 18 has fallen to atmospheric, the pressure operating outwardly onthe O-ring 58 also recedes to atmosphere and the split ring retractsinwardly substantially to the position shown in FIG. 3.

As the pressure in the reservoir falls below -a predetermined value, thespring 41 operates on the piston 28 to move it upwardly toward theposition of FIG. 1 but so long as the valve 24 is open the pressure inthe inlet eavity remains at atmospheric and the split ring 60 remains inthe retracted position of FIG. 3. Thus as the valve approaches itsclosed position the split ring 60 no longer provides an increasedpressure receiving area so that there is no danger of pressureaccumulating outwardly of the valve 24 as it approaches closing so as toimpede its moving cleanly and positively into its fully closed positionso that pressure is again delivered to the reservoir through the checkvalve 32 as previously explained. On closing snap action is realized bythe near seating f the valve 24 which causes the pressure in cavity 18to increase from atmosphere. Since the area of piston 28 is larger thanthe area of the valve 24 the result is a positive upward snap closing ofthe valve 24. As the pressure again builds up in the reservoir and inthe inlet cavity 18 it again operates on the O-ring 58 to expand thisradially outwardly to move the split ring into its restricting positionof FIG. 2 in readiness to provide added area for snap action of thevalve 24 as soon as it is cracked by the build up of pressure in thereservoir and in the inlet cavity 18.

The embodiment shown in FIG. 4 is functionally substantially identicalto the arrangement described in FIGS.

1 through 3, and like reference characters refer to like parts, exceptthat in lieu of a split ring there is substituted an annular garterspring 72 which expands and contracts uniformly throughout itscircumference. The spring 72 is coated and filled with rubber and can beexpanded outwardly by the O-ring 58 into direct engagement with theannular wall 74 of a counterbore 76 having substantially greater depththan the cavity 68 in the embodiments of FIGS. 1 and 3. As the garterspring is expanded outwardly it very nearly closes oif the upper end ofa vertical relief groove 78 in the side wall 74 so that initially,following cracking of the valve 24, the fluid pressure in the cavity 18operates on the added area defined by the outer diameter of the expandedgarter spring 72 so as to move the valve and piston downwardly with asnap action until the inlet cavity 18 is in free communication throughthe exhaust port 22 with relief passage 78 whereupon the inlet cavity 18recedes to atmospheric pressure and the O-ring and garter spring retractinwardly so as to provide freedom of communication entirely around theperiphery of the grooved member 25 which has substantially less diameterthan that of the counterbore 76. The garter spring 72 and the O-ring 58,as in the first embodiment, remain in their re tracted position untilthe valve 24 has moved with positive action into its closed position.

From the foregoing description, it will now be seen that the provisionof means for automatically adding and subtracting motive areas inaccordance with the need for such areas has been provided by the presentinvention and that the arrangement of the invention entirely eliminatesany sponginess or slowness of response, particularly during valveclosing, which may occur where an added area is present irrespective ofwhether the valve is to be moved to its open position, where added areais necessary, or to closed position where the added area is oftenundesirable. Those skilled in the art will, of course, recognize thatthe valve of the invention is susceptible of .a variety of changes andmodifications without however, departing from the scope and spirit ofthe appended claims.

What is claimed:

1. A valve comprising a body having an inlet cavity connected to asource of fluid pressure, an exhaust cavity in said body, a portconnecting said inlet and exhaust cavities, a valve in the exhaustcavity controlling said port and exposed at all times through said portto pres sure in said inlet cavity urging said valve to open position,resilient means urging said valve at all times to closed position inopposition to the pressure in said inlet cavity, a pressure responsiveexpansiole element integrally connected to said exhaust valve formovement therewith, fluid pressure conduit means connecting said elementat all times with the pressure in said inlet cavity for expanding saidelement into close adjacency with the wall of said exhaust cavity toafford an added motive area for said valve to effect movement of same toopen position with a snap action upon cracking thereof, second fluidconduit means cooperating with said expansible element for freelyconnecting said exhaust cavity to atmosphere after a predeterminedmovement of said valve and element in an opening direction, and meansautomatically retracting said element to a position substantially spacedfrom the wall of said cavity when the pressure in said inlet cavity isat a predetermined low value.

2. A valve comprising a body having an inlet cavity connected to asource of fluid pressure, an exhaust cavity having an annular side wallin said body, a port connecting said inlet and exhaust cavities, a valvein the exhaust cavity controlling said port and exposed at all timesthrough said port to pressure in said inlet cavity urging said valve toopen position, resilient means urging said valve at all times to closedposition in opposition to the pressure in said inlet cavity, a pressureresponsive radially expansible annular element in said exhaust cavityand integrally connected to said exhaust valve on the side thereofopposite said port and movable with said valve, fluid pressure conduitmeans connecting said element at all times with the pressure in saidinlet cavity for expanding said element radially into close adjacencywith the wall of said exhaust cavity to afford an added motive area forsaid valve to effect movement of the same to open position with a snapaction upon cracking thereof, second fluid conduit means cooperatingwith said expansible element for freely connecting said exhaust cavityto atmosv phere after a predetermined movement of said valve and elementin an opening direction, and means automatically retracting said elementto a position substantially spaced from the wall of said cavity when thepressure in said inlet cavity is at a predetermined low value.

3. The valve of claim 2 wherein the wall of said exhaust cavity is oflimited depth and where said second conduit means is afforded by spacingbetween said exhaust and said wall upon movement of said expansibleelement to a position beyond said wall.

4. The valve of claim 2 wherein the wall of said exhaust cavity is ofsubstantial depth and wherein said second fluid conduit means comprisesa groove in the wall having an outer end open to atmosphere and an innerend below which the expansible element is movable to freely connect saidexhaust cavity to atmosphere.

5. A valve comprising a body having an inlet cavity connected to asource of fluid pressure, an exhaust cavity in said body, a portconnecting said inlet and exhaust cavities, a valve in the exhaustcavity controlling said port and exposed at all times through said portto pressure in said inlet cavity urging said valve to open position,resilient means operating at all times on said valve to urge it toclosed position, fluid pressure responsive means in said valve bodyoperating on said valve upon movement thereof to open position to retainit opened in opposition to said resilient means so long as the pressureon said fluid pressure responsive means is above a predetermined value,a pressure responsive expansible element integrally connected to saidexhaust valve for movement therewith, fluid pressure conduit meansconnecting said element at all times with the pressure in said inletcavity for expanding said element into close adjacency with the wall ofsaid exhaust cavity to afford an added motive area for said valve toeffect movement of the same to open position with a snap action uponcracking thereof, second fluid conduit means cooperating with saidexpansible element for freely connecting said exhaust cavity toatmosphere after a predetermined movement of said valve and element inan opening direction, and means automatically retracting said element toa position substantially spaced from the wall of said cavity so as notto impede the return of said exhaust valve to closed position when thepressure on the pressure responsive element has fallen below saidpredetermined value.

6. In combination with a valve body including an inlet cavity having aninlet port, an exhaust cavity having an annular wall, a portinterconnecting said inlet and exhaust cavities, said exhaust cavitycontrolling said port and responsive to pressure in said inlet cavityfor movement to open position, resilient means urging said valve at alltimes to closed position but yielding to enable said valve to open whenthe force of pressure in said inlet cavity acting on said valve is abovea predetermined value, and fluid pressure responsive means for retainingsaid valve open upon movement thereof to open position in opposition tosaid resilient means so long as the pressure acting upon said pressureresponsive means is above a predetermined value, the invention whichcomprises an annular disc-like element in said exhaust cavity andintegrally connected to said valve on the sid thereof opposite saidport, said disc-like element having substantially less diameter thansaid exhaust cavity, an annular outwardly open groove through theperiphery of said disclike element, a resilient expansible element insaid groove and movable between a normally retracted position ofsubstantially less diameter than said exhaust cavity to an expandedposition wherein said element extends radially outwardly of said grooveand into close adjacency with th side wall of said cavity, an expansibleO-ring in said groove inwardly of said expansible element and slidinglyand sealingly engaging the opposed side faces of said groove, and fluidpassage means connecting said groove inwardly of said O-ring at alltimes with the pressure in said inlet cavity, and second fluid conduitmeans cooperating with said expansible element for freely connectingsaid exhaust cavity with atmosphere after predetermined movement of saidvalve and said element in a valve opening direction.

7. The combination of claim 6 wherein said expansible element comprisesa split expansion ring.

8. The combination of claim 6 wherein said expansible element comprisesa garter spring and resilient yielding material embedding andsurrounding said spring.

9. The combination of claim 6 including means for positively limitingthe extent of expansion of said expansible element, said meanscomprising a cup-shaped element of a predetermined diameter greater thansaid disc-like element and having an upstanding annular wall whichaffords an abutment for said element upon expansion thereof.

References Cited UNITED STATES PATENTS 2,507,384 5/1950 Schneck 137-1082,585,045 2/1952 Schmidlin 137-108 X 2,749,935 6/1956 Heard 13710'8 X3,086,548 4/1963 Galiger 137116.5 3,329,154 7/1967 Morse 137-116 WILLIAMF. ODEA, Primary Examiner.

W. H. WRIGHT, Assistant Examiner.

1. A VALVE COMPRISING A BODY HAVING AN INLET CAVITY CONNECTED TO ASOURCE OF FLUID PRESSURE, AN EXHAUST CAVITY IN SAID BODY, A PORTCONNECTING SAID INLET AND EXHAUST CAVITIES, A VALVE IN THE EXHAUSTCAVITY CONTROLLING SAID PORT AND EXPOSED AT ALL TIMES THROUGH SAID PORTTO PRESSURE IN SAID INLET CAVITY URGING SAID VALVE TO OPEN POSITION,RESILIENT MEANS URGING SAID VALVE AT ALL TIMES TO CLOSED POSITION INOPPOSITION TO THE PRESSURE IN SAID INLET CAVITY, A PRESSURE RESPONSIVEEXPANSIBLE ELEMENT INTEGRALLY CONNECTED TO SAID EXHAUST VALVE FORMOVEMENT THEREWITH, FLUID PRESSURE CONDUIT MEANS CONNECTING SAID ELEMENTAT ALL TIMES WITH THE PRESSURE IN SAID INLET CAVITY FOR EXPANDING SAIDELEMENT INTO CLOSE ADJACENCY WITH THE WALL OF SAID EXHAUST CAVITY TOAFFORD AN ADDED MOTIVE AREA FOR SAID